This invention relates to improvements in shear blades and more particularly to an improved shear blade construction as used in the logging and fireplace wood cutting industry.
Hydraulically activated shears have been used successfully for a number of years, either as a part of a tree harvesting apparatus or as part of a shearing attachment. Such shears generally comprise either a single pivotal blade acting against an anvil, a pair of opposing scissor like blades, or a guillotine like shear.
Since their inception log and tree shears have proved to be quite effective and efficient with regards to speed of operation, capacity, and reliability as compared to conventional sawing. However, there are certain areas in which such mechanical shears still fall short of desired results.
One problem area is in the quality of the cut sections. While shears are generally capable of cutting a log quickly, they tend to split and otherwise damage a portion of the log on either side of the cut. Any such damage results in waste and unsightly sections.
Another problem area is the amount of force necessary to force the shear through the log as this force can put un-acceptable loads on other components in the system and require a substantial power source equal to the task.
Still another problem is the shear blade deflection which occurs as the shear moves through the log, resulting in bending or breaking the blade.
Yet another problem is the required sharpening of the shear which occurs when the cutting edge is dulled by the brute force of pushing the shear straight through the log.
Still another problem is the thickness of the blade which must be substantial in order to keep the blade from bending or breaking which becomes self defeating as the thicker the blade, the more force is required to force it through the log.
Other problems are apparent in the guillotine type of blades which require long guide rails which are easily clogged with debris which causes the blade to bind and fail.